I have several of these - Calumet sold off a bunch cheap via eBay a few years ago.
British made Quarter plate cameras took book-form holders or double darkslides with grooverd edges, alternately there were German & similar style UK, French etc 9x12 camears with quarter plate backs, these holders are single sided and very thin.
Kodak did import a few Graflex cameras though. I knew Graflex made quarter plate holders but wasn't aware Fidelity made them they weren't advertsied here in the UK
Last year there was a stall holder at Wolverhampton camera fair with some large boxes full of different plate & film holders (all inexpensive no regulat 5x4 etyc though) and someone like that's the best place to get what Steve needs.
I ended up with a 1/4 pt Speed Graphic with no DDS, but the correct RFB - I have toyed with the idea of a few 1/4pt DDS for it but reading this thread has left me confuseder than ever and detirmined to stay with 5x4 and 10x8 as I understand them
I will just use the 1/4pt SG with the RFB for something - Actually nothing, so I will offer it for sale - Too much confusion with too many formats
Yep, the 2-1/4 x 3-1/4 is probably the most obtuse film size ever.
Europe: 6.5x9 sheet film.
England: 2-1/2 x 3-1/2 or 2-1/4 x 3-1/4 sheet film.
USA : 2-1/4 x 3-1/4 sheet film.
Roll film: 120 or 620; 6x9 (2-1/4 x 3-1/4) or 6x6 (2-1/4 x2-1/4) or 6x7 (2-1/4 x 2-3/4), or 6x4.5 (2-1/2 x 1-5/8). Then there is 70mm cine film, 116 or 616 roll film (2-1/2 wide), and a lot of other obsolete film sizes.
The thing about all of those despite often being called the same thing, they are all slightly different than each other.
About the only English size sheet film that was popular in Europe and the USA was 3-1/4 x 4-1/4 (quarter plate size). Plate sizes came about due to the standard sizes of plate glass prior to the big rollerized manufacture. 6-1/2 x 8-1/2 in England, 5x7 or 8x10 in the USA, 18cm x 24cm (I think) in Europe. Those were often cut in half or in quarters for use in smaller cameras.
Roll film on the other hand was usually based on the size and shape of the spools, so there were often many different roll films that had similar, but not exactly the same size negatives. The largest roll film negative I know of was 5in x 7in. 5x7 seemed to have been the upper size limit for hand held cameras.
I have a 23 Speed Graphic that I used a lot in the late '50s and early '60s. I have two negative carriers for my Omega B8 enlarger; one for 2 1/4 x 3/1/4 sheet film and one for 120 roll film 2 1/4 x 3 1/4 images. The third size (which I haven't seen mentioned here) was the 2 1/4 x 3 1/4 film pack. The film size was wider than 120 roll film and needed cutting to work in the roll film holder (if I remember correctly).